Solventless addition-curable pressure sensitive silicone adhesive composition and adhesive article

Abstract

A solventless addition-curable pressure sensitive silicone adhesive composition is provided. The composition comprises (A) an alkenyl group-containing polydiorganosiloxane; (B) a condensation product of (a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain and (b) a polyorganosiloxane containing R 1 3 SiO 1/2 unit and SiO 2 unit as critical components and also a HOSiO 3/2 unit in the molecule; (C1) a polyorganohydrosiloxane having at least three SiH groups per molecule; (C2) a polydiorganohydrosiloxane having SiH group on opposite ends; and (D) a platinum group metal catalyst. Use of the present composition enables production of a pressure sensitive adhesive agent having flexibility, pressure sensitive adhesiveness, and heat resistance, and the present composition is particularly effective for use as a buffer member having pressure sensitive adhesiveness.

The invention claimed is: 
     
       1. A solventless addition-curable pressure sensitive silicone adhesive composition, consisting of:
 (A) a polydiorganosiloxane having at least two alkenyl group-containing organic groups per molecule represented by formula (1):
   X b R 3-b SiO—[R 2 SiO] a —SiX b R 3-b   (1)
 
 
  wherein X is an alkenyl group-containing organic group containing 2 to 10 carbon atoms, R is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms, a is an integer of 50≦a ≦2,000, and b is an integer of 1 to 3, 
 (B) a condensation product of the SiOR 2  group of the following component (a) with the SiOH group of the following component (b):
 (a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain represented by formula (2):
   (R 2 O)R 1   2 SiO—[R 1   2 SiO] c —SiR 1   2 (OR 2 )  (2)
 
 
 
  wherein R 1  is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms excluding alkenyl group-containing organic groups, R 2  is hydrogen atom or R 1 , and c is an integer of 50≦c≦2,000, and
 (b) a polyorganosiloxane containing R 1   3 SiO 1/2  unit (wherein R 1  is as defined above), SiO 2  unit, and a siloxane unit having hydroxyl group bonded to the silicon atom wherein molar ratio of the R 1   3 SiO 1/2  unit to the SiO 2  unit is 0.6 to 1.0 and content of the hydroxyl group is at least 0.1% by weight and less than 1.8% by weight, 
 
 with the proviso that the component (A) is 10 to 90 parts by weight, the component (a) is 5 to 60 parts by weight, and the component (b) is 5 to 60 parts by weight in relation to 100 parts by weight of the total of the components (A), (a), and (b), 
 (C) component (C1) of a polyorganohydrosiloxane having at least three SiH groups per molecule, or 
 the component (C1) and component (C2) of a polydiorganohydrosiloxane having SiH group on opposite ends represented by formula (3):
   HR 1   2 SiO—[R 1   2 SiO] d —SiR 1   2 H  (3)
 
 
  wherein R 1  is as defined above and d is an integer of 5≦d≦500 
  (with the proviso that molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is 0.2 to 15, and molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is 0 to 5), 
 (D) a platinum group metal catalyst (1 to 500 ppm by weight in terms of the platinum group metal in relation to the total of the components (A), (a), and (b)), and 
 (E) a reaction regulator agent at 0.005 to 5 parts by weight in relation to 100 parts by weight of the total of components (A), (a), and (b). 
 
     
     
       2. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 1  wherein the molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is in the range of 0.3 to 5, and the molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is in the range of 0.2 to 3. 
     
     
       3. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 1  wherein the composition has a viscosity at 25° C. of 1,000 to 500,000 mPa·s. 
     
     
       4. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 1  wherein the composition has a probe tack of 50 to 500 gf when measured by pressing a probe with a diameter of 5 mm having a smooth tip surface against an adhesive sheet prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 0.5 mm on a polyimide film having a thickness of 50 μm at right angle and at a speed of 1 cm/second so that the contact pressure is 20 g/cm 2 , and measuring the force required for detaching the probe after pressing the probe for 1 second. 
     
     
       5. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 1  wherein the composition has an adhesiveness of 0.05 to 4.0 N/25 mm when measured by attaching an adhesive sheet with a width of 25 mm prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 40 μm on a polyimide film having a thickness of 25 μm on a stainless steel plate, and peeling the adhesive tape therefrom in the direction of 180° at a speed of 300 mm/minute. 
     
     
       6. An adhesive article having buffering properties (excluding those for aerospace) prepared by coating, curing, or molding the solventless addition-curable pressure sensitive silicone adhesive composition of  claim 1  to a thickness of at least 10 μm. 
     
     
       7. A solventless addition-curable pressure sensitive silicone adhesive composition, consisting of:
 (A) a polydiorganosiloxane having at least two alkenyl group-containing organic groups per molecule represented by formula (1):
   X b R 3-b SiO—[R 2 SiO] a —SiX b R 3-b   (1)
 
 
  wherein X is an alkenyl group-containing organic group containing 2 to 10 carbon atoms, R is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms, a is an integer of 50≦a ≦2,000, and b is an integer of 1 to 3, 
 (B) a condensation product of the SiOR 2  group of the following component (a) with the SiOH group of the following component (b): 
 (a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain represented by formula (2):
   (R 2 O)R 1   2 SiO—[R 1   2 SiO] c —SiR 1   2 (OR 2 )  (2)
 
 
  wherein R 1  is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms excluding alkenyl group-containing organic groups, R 2  is hydrogen atom or R 1 , and c is an integer of 50≦c≦2,000, and 
 (b) a polyorganosiloxane containing R 1   3 SiO 1/2  unit (wherein R 1  is as defined above), SiO 2  unit, and a siloxane unit having hydroxyl group bonded to the silicon atom wherein molar ratio of the R 1   3 SiO 1/2  unit to the SiO 2  unit is 0.6 to 1.0 and content of the hydroxyl group is at least 0.1% by weight and less than 1.8% by weight, 
  with the proviso that the component (A) is 10 to 90 parts by weight, the component (a) is 5 to 60 parts by weight, and the component (b) is 5 to 60 parts by weight in relation to 100 parts by weight of the total of the components (A), (a), and (b), 
 (C) component (C1) of a polyorganohydrosiloxane having at least three Si groups per molecule, or 
 the component (C1) and component (C2) of a polydiorganohydrosiloxane having SiH group on opposite ends represented by formula (3):
   HR 1   2 SiO—[R 1   2 SiO] d —SiR 1   2 H  (3)
 
 
  wherein R 1  is as defined above and d is an integer of 5≦d≦500 
  (with the proviso that molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is 0.2 to 15, and molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is 0 to 5), 
 (D) a platinum group metal catalyst (1 to 500 ppm by weight in terms of the platinum group metal in relation to the total of the components (A), (a), and (b)), 
 (E) a reaction regulator agent at 0.005 to 5 parts by weight in relation to 100 parts by weight of the total of components (A), (a), and (b), and 
 at least one component selected from the group consisting of a non-reactive polyorganosiloxane, an antioxidant, a light stabilizer, a flame retardant, an activator, an antistatic agent, a colorant, and a filler. 
 
     
     
       8. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 7 , wherein the molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is in the range of 0.3 to 5, and the molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is in the range of 0.2 to 3. 
     
     
       9. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 7 , wherein the composition has a viscosity at 25° C. of 1,000 to 500,000 mPa·s. 
     
     
       10. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 7 , wherein the composition has a probe tack of 50 to 500 gf when measured by pressing a probe with a of diameter 5 mm having a smooth tip surface against an adhesive sheet prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 0.5 mm on a polyimide film having a thickness of 50 μm at right angle and at a speed of 1 cm/second so that the contact pressure is 20 g/cm 2 , and measuring the force required for detaching the probe after pressing the probe for 1 second. 
     
     
       11. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 7 , wherein the composition has an adhesiveness of 0.05 to 4.0 N/25 mm when measured by attaching an adhesive sheet with a width of 25 mm prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 40 μm on a polyimide film having a thickness of 25 μm on a stainless steel plate, and peeling the adhesive tape therefrom in the direction of 180° at a speed of 300 mm/minute. 
     
     
       12. An adhesive article having buffering properties (excluding those for aerospace) prepared by coating, curing, or molding the solventless addition-curable pressure sensitive silicone adhesive composition of  claim 7 , to a thickness of at least 10 μm. 
     
     
       13. A solventless addition-curable pressure sensitive silicone adhesive composition, comprising:
 (A) a polydiorganosiloxane having at least two alkenyl group-containing organic groups per molecule represented by formula (1);
   X b R 3-b SiO—[R 2 SiO] a —SiX b R 3-b   (1)
 
 
  wherein X is an alkenyl group-containing organic group containing 2 to 10 carbon atoms, R is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms, a is an integer of 50≦a ≦2,000, and b is an integer of 1 to 3, 
 (B) a condensation product of the SiOR 2  group of the following component (a) with the SiOH group of the following component (b): 
 (a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain represented by the following general formula (2):
   (R 2 O)R 1   2 SiO—[R 1   2 SiO] c —SiR 1   2 (OR 2 )  (2)
 
 
  wherein R 1  is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms excluding alkenyl group-containing organic groups, R 2  is hydrogen atom or R 1 , and c is an integer of 50≦c≦2,000, and 
 (b) a polyorganosiloxane containing R 1   3 SiO 1/2  unit (wherein R 1  is as defined above), SiO 2  unit, and a siloxane unit having hydroxyl group bonded to the silicon atom wherein molar ratio of the R 1   3 SiO 1/2  unit to the SiO 2  unit is 0.6 to 1.0 and content of the hydroxyl group is at least 0.1% by weight and less than 1.8% by weight, 
  with the proviso that the component (A) is 10 to 90 parts by weight, the component (a) is 5 to 60 parts by weight, and the component (b) is 5 to 60 parts by weight in relation to 100 parts by weight of the total of the components (A), (a), and (b), 
 (C) component (C1) of a polyorganohydrosiloxane having at least three SiH groups per molecule, or 
 the component (C1) and component (C2) of a polydiorganohydrosiloxane having SiH group on opposite ends represented by formula (3):
   HR 1   2 SiO—[R 1   2 SiO] d —SiR 1   2 H  (3)
 
 
  wherein R 1  is as defined above and d is an integer of 5≦d≦500 
  (with the proviso that molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is 0.2 to 15, and molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is 0 to 5), and 
 (D) a platinum group metal catalyst (1 to 500 ppm by weight in terms of the platinum group metal in relation to the total of the components (A), (a), and (b)), 
 wherein said composition has an adhesiveness of 0.05 to 4.0 N/25 mm when measured by attaching an adhesive sheet with a width of 25 mm prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 40 μm on a polyimide film having a thickness of 25 μm on a stainless steel plate, and peeling the adhesive tape therefrom in the direction of 180° at a speed of 300 mm/minute. 
 
     
     
       14. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 13 , wherein the molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is in the range of 0.3 to 5, and the molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is in the range of 0.2 to 3. 
     
     
       15. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 13 , wherein the composition has a viscosity at 25° C. of 1,000 to 500,000 mPa·s. 
     
     
       16. A solventless addition-curable pressure sensitive silicone adhesive composition according to  claim 13 , wherein the composition has a probe tack of 50 to 500 gf when measured by pressing a probe with a of diameter 5 mm having a smooth tip surface against an adhesive sheet prepared by forming a pressure sensitive adhesive layer of the pressure sensitive silicone adhesive composition to a thickness of 0.5 mm on a polyimide film having a thickness of 50 μm at right angle and at a speed of 1 cm/second so that the contact pressure is 20 g/cm 2 , and measuring the force required for detaching the probe after pressing the probe for 1 second. 
     
     
       17. An adhesive article having buffering properties (excluding those for aerospace) prepared by coating, curing, or molding the solventless addition-curable pressure sensitive silicone adhesive composition of  claim 13 , to a thickness of at least 10 μm.